Says it is fast, but presents zero benchmarks to demonstrate it is actually fast or even “faster”. It is shameful to make up adjectives just to sound cool.

vsock is pretty widely used, and if you're using virtio-vsock it should be fast. Anyway if you want to do some quick benchmarks and have an existing Linux VM on a libvirt host:

(1) 'virsh edit' the guest and check it has '<vsock/>' in the <devices> section of the XML.

(2) On the host:

  $ nbdkit memory 1G --vsock -f

  $ nbdinfo 'nbd+vsock://2'

And then you can try using commands like nbdcopy to copy data into and out of the host RAM disk over vsock. eg:

  $ time nbdcopy /dev/urandom 'nbd+vsock://2' -p
  $ time nbdcopy 'nbd+vsock://2' null: -p